What is arguably more interesting than any of that is why on earth celebrities choose to smoke at all?
Hollywood stardom and celebrity status is a superficial world almost entirely based on looks and image. As such, it's truly astounding to see so many celebrities smoking.
Surely we all know by now just how great an impact cigarette smoke has on our skin. Even if, by some strange twist of fate, celebrities themselves manage to remain ignorant of the way smoking effects skin aging, don't they have armies of advisors and image consultants to keep them on track?
Surely someone in the inner circle tells them about the results of recent research - how smoking dehydrates the skin, destroys vitamin C, damages collagen, accelerates wrinkling and produces the classic ‘smoker’s face’?.
It’s impossible to believe that highly paid, news-savvy and reasonably intelligent people can remain ignorant of these essential facts. They must know that smoking will damage their looks and prematurely age them and they choose to carry on - all the while spending small fortunes on personal trainers, nutritionists, cosmetic surgeons and anti-aging creams and lotions.
Could it be that the stars themselves have been influenced by the glamour that was once associated with cigarettes? Perhaps if you spend long enough in the fantasy world of film you start to believe in the celluloid image. Just like Gloria Swanson in 'Sunset Boulevard' they've lost touch with reality.
After all, it's not so long ago that everybody who was a somebody in Hollywood smoked and was proud of it. Cigarette smoking was glamorous and sophisticated. Just think of the iconic image of Audrey Hepburn in 'Breakfast at Tiffany's' as Holly Golightly - posing elegantly with her long cigarette holder, upswept chignon and little black dress.
What's not so elegant of course is the way Audrey Hepburn succumbed to the smoking habit herself. Ignoring her mother's 'beauty tip' to: "keep to six cigarettes a day only", Hepburn managed two or three packs at her worst times - even smoking in her nun's habit on the set of 'The Nun's Story' and chain smoking her way through 'My Fair Lady'.
Unsurprisingly, she suffered from asthma for most of her life and died of cancer at only 63,looking frail and old for her years. Not the kind of ending we like to imagine for the sublime Holly Golightly.
There's no doubt that the very nature of the movie business has caused many a celebrity to start treading the nicotine path. Smoking is as common in movies today as it was back in the 1950's although overall smoking in the population at large (the Western half anyway) has reduced. Could it be that a cigarette has become the film prop of choice for actors looking for an easy way to inhabit another skin?
For some celebrities - tired of the constant criticism and the ciggy shots splashed across the tabloids - a kind of smoking defiance has crept in. As Gwyneth Paltrow once said, "I smoke and I'm not going to stop!". Paltrow - famous for getting through a pack of Camel Lights a day in her teens and twenties - has only very recently quit smoking. Perhaps she started to wonder how her fine, fair skin and ethereal beauty would cope with the collagen depletion in her forties and fifties.
Some celebrities keep going with the smoking habit whatever the consequences - even if it impacts on their closest relationships. It's well known that smoking was a bone of contention between Brad Pitt and Jennifer Anniston during their marriage. Brad Pitt is on record as saying how much he hated his ex-wife's chain smoking. His disapproval didn't cut much ice with Jennifer though - as recent paparazzi photos show. You have to ask why one of the world’s most loved and naturally attractive women would do this to themselves?
Similarly, iconic top model Kate Moss is regularly photographed with her cigarette, a lighter and a mobile phone as her only fashion accessory. As a supreme super model its probably not surprising that Moss still manages to appear effortlessly elegant and beautiful however she's photographed - at least for now.
She certainly shows no signs of wanting to quit smoking any time soon. Perhaps like so many in her world - she associates smoking with thinness. Or perhaps, for her, it's the least troubling of her addictions.
When celebrities do chose to quit its fascinating that the reasons given are so often not about looks or even health. Catherine Zeta-Jones for instance, quit smoking - so she said - because she didn't want her children to start asking questions. Not as you might have thought - because beauty is her personal trademark and smoking would kick-start skin aging and undermine her potential to earn huge sums of money.
Whatever the reasons celebrities have for smoking or for deciding to quit - the truth about skin damage and smoking very rarely features as a major factor in the debate. Well – maybe it’s about time it did.
So, some advice to all you celebrity smokers out there - carry on smoking if you want - but don't expect your fickle public not to notice the effect on your looks.
And when you hit a deluded (or regretful) middle age you may still be able to say, like Gloria Swanson in 'Sunset Boulevard': "I'm ready for my close-up now Mr de Mille" - but only if it's filmed in heavy soft-focus, expertly back-lit and then extensively re-touched afterwards.
